diff --git a/crates/erg_compiler/context/initialize/classes.rs b/crates/erg_compiler/context/initialize/classes.rs
index 05a31611..725a5fa2 100644
--- a/crates/erg_compiler/context/initialize/classes.rs
+++ b/crates/erg_compiler/context/initialize/classes.rs
@@ -4023,6 +4023,12 @@ impl Context {
             Immutable,
             Visibility::BUILTIN_PRIVATE,
         );
+        let coro_t = poly(COROUTINE, vec![ty_tp(T.clone())]);
+        let mut coroutine = Self::builtin_poly_class(COROUTINE, vec![PS::t_nd(TY_T)], 2);
+        coroutine.register_superclass(mono(SUBROUTINE), &subr);
+        coroutine
+            .register_trait(self, poly(OUTPUT, vec![ty_tp(T.clone())]))
+            .unwrap();
         // TODO: non-builtin
         /* Dimension */
         let Ty = type_q("Ty");
@@ -4644,6 +4650,7 @@ impl Context {
         self.register_builtin_type(set_mut_t, set_mut_, vis.clone(), Const, Some(SET));
         self.register_builtin_type(mono(SUBROUTINE), subr, vis.clone(), Const, Some(SUBROUTINE));
         self.register_builtin_type(generator_t, generator, vis.clone(), Const, Some(GENERATOR));
+        self.register_builtin_type(coro_t, coroutine, vis.clone(), Const, Some(FUNC_COROUTINE));
         self.register_builtin_type(dimension_t, dimension, vis.clone(), Const, Some(DIMENSION));
         self.register_builtin_type(
             mono(BASE_EXCEPTION),
diff --git a/crates/erg_compiler/context/initialize/mod.rs b/crates/erg_compiler/context/initialize/mod.rs
index 55e2c6df..04180c38 100644
--- a/crates/erg_compiler/context/initialize/mod.rs
+++ b/crates/erg_compiler/context/initialize/mod.rs
@@ -553,6 +553,8 @@ const FUNC_NEARLY_EQ: &str = "nearly_eq";
 const FUNC_RESOLVE_PATH: &str = "ResolvePath";
 const FUNC_RESOLVE_DECL_PATH: &str = "ResolveDeclPath";
 const FUNC_PROD: &str = "prod";
+const COROUTINE: &str = "Coroutine";
+const FUNC_COROUTINE: &str = "coroutine";
 
 const OP_EQ: &str = "__eq__";
 const OP_HASH: &str = "__hash__";
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/__init__.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/__init__.d.er
new file mode 100644
index 00000000..7db45402
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/__init__.d.er
@@ -0,0 +1,19 @@
+{.BaseEventLoop!; .Server!} = import "base_events"
+{.iscoroutine;. iscoroutinefunction;} = pyimport "coroutines"
+{
+    .AbstractEventLoop!;
+    .AbstractEventLoopPolicy!;
+    .AbstractServer!;
+    .Handle!;
+    .TimerHandle!;
+} = pyimport "events"
+{
+    .LifoQueue!;
+    .PriorityQueue!;
+    .Queue!;
+    .QueueEmpty;
+    .QueueFull;
+} = pyimport "queues"
+{.Runner!; .run!;} = pyimport "runners"
+{.Task!; .current_task!; .gather!; .sleep!;} = pyimport "tasks"
+{.to_thread!;} = pyimport "threads"
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/base_events.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/base_events.d.er
new file mode 100644
index 00000000..f162e5e5
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/base_events.d.er
@@ -0,0 +1,3 @@
+.BaseEventLoop!: ClassType
+
+.Server!: ClassType
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/coroutines.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/coroutines.d.er
new file mode 100644
index 00000000..dc1ac432
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/coroutines.d.er
@@ -0,0 +1,2 @@
+.iscoroutinefunction: (obj: Obj) -> Bool
+.iscoroutine: (obj: Obj) -> Bool
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/events.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/events.d.er
new file mode 100644
index 00000000..86d50965
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/events.d.er
@@ -0,0 +1,8 @@
+.Handle!: ClassType
+
+.TimerHandle!: ClassType
+.TimerHandle! <: Handle!
+
+.AbstractServer!: ClassType
+.AbstractEventLoop!: ClassType
+.AbstractEventLoopPolicy!: ClassType
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/futures.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/futures.d.er
new file mode 100644
index 00000000..f7848d17
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/futures.d.er
@@ -0,0 +1,11 @@
+.Future!: ClassType
+.Future!.
+    result: (self: Ref Future!) -> Obj
+    exception: (self: Ref Future!) -> Exception
+    done: (self: Ref Future!) -> Bool
+    cancelled: (self: Ref Future!) -> Bool
+    set_result!: (self: RefMut Future!, result: Obj) => NoneType
+    set_exception!: (self: RefMut Future!, exception: Exception) => NoneType
+    cancel!: (self: RefMut Future!, msg := Str) => Bool
+
+.isfuture: (obj: Obj) -> Bool
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/queues.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/queues.d.er
new file mode 100644
index 00000000..79018b21
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/queues.d.er
@@ -0,0 +1,13 @@
+.QueueEmpty: ClassType
+.QueueEmpty <: BaseException
+
+.QueueFull: ClassType
+.QueueFull <: BaseException
+
+.Queue!: ClassType
+
+.PriorityQueue!: ClassType
+.PriorityQueue! <: Queue!
+
+.LifoQueue!: ClassType
+.LifoQueue! <: Queue!
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/runners.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/runners.d.er
new file mode 100644
index 00000000..804809de
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/runners.d.er
@@ -0,0 +1,8 @@
+.Runner!: ClassType
+.Runner!.
+    run!: (self: Runner!, coro: GenericCallable, debug := Bool) => NoneType
+    close!: (self: Runner!) => NoneType
+    get_loop!: (self: Runner!) => NoneType
+
+# TODO: return value
+.run!: (coro: GenericCallable, debug := Bool) => NoneType
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/tasks.d.er
similarity index 51%
rename from crates/erg_compiler/lib/pystd/asyncio.d.er
rename to crates/erg_compiler/lib/pystd/asyncio.d/tasks.d.er
index 4844fdba..1e176943 100644
--- a/crates/erg_compiler/lib/pystd/asyncio.d.er
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/tasks.d.er
@@ -1,4 +1,5 @@
-# TODO: return value
-.run!: (coro: GenericCallable, debug := Bool) => NoneType
-.sleep!: (delay: Float) => NoneType
+.Task!: ClassType
+
+.current_task!: (loop := Obj) => Task!
 .gather!: (*coros: GenericCallable) => NoneType
+.sleep!: (delay: Float) => NoneType
diff --git a/crates/erg_compiler/lib/pystd/asyncio.d/threads.d.er b/crates/erg_compiler/lib/pystd/asyncio.d/threads.d.er
new file mode 100644
index 00000000..393a9167
--- /dev/null
+++ b/crates/erg_compiler/lib/pystd/asyncio.d/threads.d.er
@@ -0,0 +1 @@
+.to_thread!: (func: GenericCallable) => Obj